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Publication Abstract from PubMed

Cryo-electron microscopy is now used as a method of choice in structural biology for studying protein synthesis, a process mediated by the ribosome machinery. In order to achieve high-resolution structures using this approach, one needs to obtain homogeneous and stable samples, which requires optimization of ribosome purification in a species-dependent manner. This is especially critical for the bacterial small ribosomal subunit that tends to be unstable in the absence of ligands. Here, we report a protocol for purification of stable 30 S from the Gram-positive bacterium Staphylococcus aureus and its cryo-EM structures: in presence of spermidine at a resolution ranging between 3.4 and 3.6 A and in its absence at 5.3 A. Using biochemical characterization and cryo-EM, we demonstrate the importance of spermidine for stabilization of the 30 S via preserving favorable conformation of the helix 44.

Stabilization of Ribosomal RNA of the Small Subunit by Spermidine in Staphylococcus aureus.,Belinite M, Khusainov I, Soufari H, Marzi S, Romby P, Yusupov M, Hashem Y Front Mol Biosci. 2021 Nov 18;8:738752. doi: 10.3389/fmolb.2021.738752. , eCollection 2021. PMID:34869582^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.